1. Field of the Invention
The present invention relates to a speech processing unit installed in a navigation system to carry out voice guidance and speech recognition.
2. Description of Related Art
Some conventional navigation systems can carry out destination setting or institution search not only by operating a remote control or mechanical switches like touch switches, but also by means of accepting a speech input and performing speech recognition.
For example, Japanese patent application laid-open No. 2000-322098 discloses a speech processing unit for a navigation system that devises the following method to increase the speech recognition reliability.
When a user operates a speech input button to request acceptance of a speech input, the speech processing unit silences output sounds from car audio equipment so that it does not detect its music or the like as noise.
With the foregoing configuration, the conventional speech processing unit can improve the recognition reliability of the input voice at the cost of the output sounds from a peripheral device such as the audio equipment, when the user operates the speech input button. Accordingly, it has a problem in that the currently output voice guidance is interrupted, or the voice guidance to be output is not actually output, thereby preventing the user from obtaining truly necessary information.